The maximum theoretical efficiency of a Carnot engine operating between reservoirs at the steam point and at room temperature is about:
A)10%
B)20%
C)50%
D)80%
E)99%

Question

Quizplus · Accepted Answer

The maximum theoretical efficiency of a Carnot engine is given by 1 - (Tc/Th), where Tc is the cold reservoir temperature and Th is the hot reservoir temperature, both in Kelvin. The steam point is 100°C (or 373K) and room temperature is about 20°C (or 293K). Thus, the efficiency = 1 - (293/373) ≈ 0.21 or 21%. The closest answer is 20%.

The Maximum Theoretical Efficiency of a Carnot Engine Operating Between